Orchids are shade-loving plants, and while they are growing they need the equivalent of the dappled sunlight they would receive growing in the tree canopy of their natural home. Too much light during the summer will harm the plants by turning the foliage a light green-yellow.

In more severe cases, direct sun will burn the leaves, causing black areas where the sun’s rays have destroyed the leaf cells.

Insufficient light, on the other hand, will create dark green leaves that can become over-extended and limp. The aim should be to give your orchids just enough light to produce a good mid-green, healthy foliage and pseudo bulbs that will develop flower spikes at the right time.

After flowering and before the new growth starts, Calanthe pseudobulbs can be taken out of their pot and left to dry until the new growth is seen.

Thunias are among the very few orchids that produce an autumn display when their leaves change colour before being shed. The leafless canes remain dormant for the winter.

Moving the orchids to a lighter area winter may be the answer, provided their temperature requirements are the same. Alternatively, electric light using horticultural fluorescent tubes above the orchids, may be the answer. However, this system requires a considerable financial outlay to be satisfactory. It grows well in colder climates and is used is northern North America with success.

In a greenhouse or heated conservatory, it becomes easier to contra:, light levels, and in the winter the orchids will benefit from full light with no risk of burning from the sun s weak rays.

Summer night-time temperatures should remain at around 13C F) with no electric heating in the achieve the higher temperature required on winter lights, you will need to provide heat for longer than is necessary with the cooler-growing types